It is conventionally known that frames of eyeglasses are produced from metals and synthetic resins. The latter has more advantages than the former in light weight and decoration.
The known frames of eyeglasses, which are produced from synthetic resin, have been conventionally produced by cutting and scraping a plate or sheet composed of fiber resins such as celluloid, cellulose acetate plastics, etc., forming a piece of frame, and flexing it. However, a high cost problem is caused by the production of such frames of eyeglasses since the aforesaid plate and sheet are expensive. Also, the production of individual frames of eyeglasses involving complicated operations is not suitable for mass production, which will cause another high cost problem. Furthermore, they are easily deformed or deteriorated by heat or humidity due to their poor physical properties, and there is the problem that the variation with time shortens their life cycle.
Therefore, a frame of eyeglasses comprising injection-molding of a synthetic resin is provided in recent years, being known to the public. This frame of eyeglasses employs a carbon-reinforced thermoplastic synthetic resin as a principle material, having better physical properties than the frame of eyeglasses made from the aforesaid plate or sheet of celluloid or cellulose acetate plastics in chemical and heat resistances. Using an injection molding machine facilitates mass production, leading to production at a relatively low cost. However, the frame of eyeglasses made from a carbon-reinforced resin short fiber as described above has low resistance to flexure, and therefore, there is the problem of being easily snapped when bent and deformed.
And, since the raw material is blackened with the carbon short fiber, there is the problem of limiting the expression of a desired color. Even though a decorative effect is expected to be obtained by forming a decorative coating layer on the black surface of the frame of eyeglasses, the black colored resin skin of the frame of eyeglasses prevents a light-colored decorative coating layer from exhibiting a brilliant color tone as expected, and all frames of eyeglasses which are made from carbon-short-fiber-reinforced resins have been therefore marketed with their naked black skin color remaining.
Moreover, in forming a decorative coating layer on the surface of the frame of eyeglasses which is made from carbon-short-fiber-reinforced resins, anti-stress-cracking qualities and peeling resistance need to be reinforced by having said coating layer thermoset. However, if nylon (polyamide) for example is employed as the synthetic resin to be reinforced with carbon short fiber which will be a raw material of the frame of eyeglasses, the decorative coating layer on the surface of the frame of eyeglasses cannot be solidified with heat since the heat resistance temperature of the nylon is at approximately 140.degree. C. or more, if it has been injection-molded. This gives rise to the problem of the deformation of the frame itself of eyeglasses if it is subjected to a high temperature for the solidification of the frame of eyeglasses.
Even if an attempt is made to seek a synthetic resin suitable for the injection molding of a frame of eyeglasses, for example, a polycarbonate regarded as an engineering plastic in these years, since the heat deformation temperature is at 120.degree. to 140.degree. C., there is a problem, similarly to the afore-description, that it is impossible to apply a decorative coating layer to be heat-hardened at a high temperature over the surface of injection molded frame of eyeglasses.